The present invention relates to a perimeter, an operational method of a perimeter, a program for realizing a perimeter, and a computer-readable recorded medium.
The following are known as previous perimeters: Goldmann perimeter of 510 model [1945], 940 model [1967]; Tubinger perimeter [1957]; Octopus perimeter [1976]. (see, for example, the nonpatent literature 1.)
The explanation of previous perimeters: Goldmann perimeter is the first brightness perimeter, adopting manual method of simultaneous recording, with 4 to 60 degrees of brightness of the visual target and 6 types of visual angle of the visual target, capable of examining visual field of visual angle, and with adjustability of its background brightness. The shortcoming is that it fails to examine the central region within 5 degrees;
Tubinger perimeter [1957] is the first practical, static perimeter, capable of examining the kinetic visual field and the visual field of color, flicker, and etc., adopting manual method of simultaneous recording, with 80 degrees of brightness of the visual target and 100 degrees of brightness of the fixation image and 5 kinds of color and 6 degrees of background brightness, and capable of examining the central and eccentric vision. Its shortcoming is in the difficulty of controlling the visual target movement, and of adjusting the visual target, fixation image, and background illumination lamp;
Octopus perimeter [1976] is the world's first fully automated, static perimeter.
Nonpatent literature 1: “The latest comprehensive dictionary of medical science”, Ishiyaku Publishers Inc., 1987, 1990.
There exists a considerable discrepancy between the chart resulted from a previous visual field examination and the shape of scotoma and blind spot true to the subject, since the shapes of scotoma and blind spot detected by previous perimeters are very rough.
It is because of relying on previous perimeters that the early detection of visual defects has been failing.
And there is the high possibility of erroneous responses made by the subject due to habituation, etc., because procedures of previous examinations are made up of very monotonous repetitions.
The aim of the present invention is, therefore, to provide a perimeter capable of reflecting, in much greater detail, the shape of the scotoma and blind spot true to a subject into the image obtained by the examination.
The aim of the present invention is also to provide a perimeter reducing the monotony seen in previous examinations of the visual field.